BirdAnalyst
Species · Delaware · BBS 2026 Release · 1966–2025

Field Sparrow Population Trend in Delaware

All statesForest birds

Field Sparrow in Delaware has fallen sharply: down 56% on the route-weighted index since 1968.

-56%Since 1968TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
17Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Field Sparrow Trends in DelawareNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc declinecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Field Sparrow has fallen sharply in Delaware: down 56% on the route-weighted index since 1968.

Field Sparrow Population Forecast in Delaware

If the recent trend holds, Field Sparrow in Delaware is projected to fall about 39% by 2030 — from 4.0 in 2025 to a central estimate of 2.4 (95% range 0.00–7.5). A 5-year backtest shows a typical error of ±56.1%, with 60% of held-out values landing inside the 95% band.

-39%Change by 2030TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
2.4Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–7.595% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±56.1%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Field Sparrow in Delaware is projected to fall about 39% by 2030 — from 4.0 in 2025 to a central estimate of 2.4 (95% range 0.00–7.5). A 5-year backtest shows a typical error of ±56.1%, with 60% of held-out values landing inside the 95% band.19662030
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20263.00.008.1
20272.90.008.0
20282.70.007.8
20292.60.007.7
20302.40.007.5

Field Sparrow Survey Routes in Delaware

Routes recording Field Sparrow in Delaware.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
Lowes Xrds1219911966
Blackbird920251994
Holleyville 2720242006
Holleyville620041966
Frankford420121966
Milton420161966
Millsboro420252017
Pepperbox420161998
Wilmington320141966
Harrington320251966
Bethany Bch319891966
Milton 2320252017
Pepperbox 2320252017
Mt Pleasant220191966
Frederica220251966
Dover219851966
Georgetown220221992

Field Sparrow Population Trend in Other States

alabamaarkansascoloradoconnecticutfloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.